I understand the reasoning behind the front/rear bias based on weight differences and could be that the difference felt and stresses induced to the mechanical parts are different MT drivetrain to AT drivetrain based on the different design and functionality of the center diff?
My tires have trouble maintaining pressure. I've had them on for over 40K miles. I always check pressure once a week and these damn things are always inconsistent. I have driven the car with a front/rear bias well over 5, sometimes 10 PSI and even side to side on the rear. By all that I have read my awd should have blown up.
And yet, not only does it still work and works great, there is no difference in drivability feel when the tires have lost some pressure.

With respect SBT, I have a lot of trouble believing you can feel 1 PSI difference.
3 to 5 or more I can see, but one PSI?

What would help put this ongoing debate to bed would be literature straight from SOA. All we have so far is the logical reasoning passed on and on. Some subscribe to it, others do not.
And to make sure I have the debate straight, some say the PSI difference is to maintain proper stance on the road (grip, steer etc), other say it has a real, negative impact on the full-time Subaru awd if pressure is ran front/rear without a bias.